In a conventional large current rectifier, a diode chip as a rectifying device has been fixed by low melting-point metal such as solder. However, because the usage of the solder including lead increases the environmental load, a solder-free system has been expected.
A rectifier having a solder-free structure is, for example, disclosed in Japanese Patent No. 3,198,693, in which the rectifier is composed of a metal stem having a male thread on the outer circumferential face thereof, a metal cap having a female thread on the inner circumferential face thereof, a lead terminal fixed to an insulator, and a diode chip provided on the stem, and by fitting the stem with the cap, one of the electrodes of the diode chip is electrically connected to the lead terminal, meanwhile the other electrode is connected to the stem. In such a conventional rectifier, solder excluding lead has been realized and utilized; however, a problem has been found that resistance increase, wire breakage, etc. of the diode chip occur in operation.